Non-uniform Quantization for Neural Network Read Voltage

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Solution Overview

Problem

Non-volatile memory devices face challenges in maintaining data integrity due to noise introduced by program disturb and inter-cell interference, which affects the voltage levels over time, requiring improved methods to determine optimal read voltage thresholds.

Innovation Solution

Implementing deep neural networks with non-uniform quantization for power-of-two computations to reduce latency and inference time, allowing for the generation of updated read voltage values in memory devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If uniform quantization is used for power-of-two computations in DNN, then implementation is simpler, but latency and inference time increase

Engineering Contradiction:
Improveimplementation simplicityVSAvoidlatency and inference time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent applies non-uniform quantization specifically to the weight parameters of the DNN, while keeping the computational structure simple. This localized application of complexity to the right component (weights) achieves fast power-of-two computations without making the entire system complex

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the quantization parameter distribution from uniform to non-uniform, where quantization levels are adapted to the actual weight distribution. This parameter change enables more efficient representation that speeds up computation while maintaining accuracy

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If non-uniform quantization is used for power-of-two computations in DNN, then latency and inference time are reduced, but quantization complexity increases

Engineering Contradiction:
Improvelatency and inference timeVSAvoidquantization complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The complex non-uniform quantization is applied only to the weight parameters, not to the entire computational process. The computational operations themselves remain simple power-of-two operations, localizing the complexity to where it provides maximum benefit

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The non-uniform quantization levels are pre-computed and stored in lookup tables before inference. This preliminary preparation eliminates the need for complex real-time calculations during inference, achieving fast execution without runtime complexity

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If standard DNN computation methods are used, then accuracy is maintained, but memory footprint and computational power requirements are high

Engineering Contradiction:
ImproveDNN accuracyVSAvoidmemory footprint and computational power
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the parameter representation from standard floating-point to non-uniform quantized integers that represent power-of-two values. This parameter transformation reduces memory footprint and computational requirements while preserving accuracy through adaptive quantization levels

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex floating-point multiplication operations with simpler integer addition and bit-shifting operations. This substitution of computational mechanics reduces the computational power required while maintaining accuracy through the non-uniform quantization scheme

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240112020A1Non-uniform quantization for flexible power-of-two computations in neural networks
Publication Date: 2024.04.04 SK HYNIX INC
  • US20240112020A1 patent drawing
  • US20240112020A1 patent drawing
  • US20240112020A1 patent drawing

AI summary

Devices, systems, and methods for improving operation of a memory device that uses a deep neural network (DNN), based on using non-uniform quantization for flexible power-of-two computations, are described. An example method includes receiving a plurality of initial weights of the DNN configured to determine a value of a read voltage associated with memory device, wherein the plurality of initial weights comprises at least one non-power-of-two quantized value or at least one floating point value. The method then aggregates the plurality of initial weights to generate a plurality of quantization functions, determines each of a plurality of quantized weights for a corresponding one of the plurality of quantization functions such that each of the plurality of quantized weights is a sum of powers-of-two, and configures the DNN to use the plurality of quantized weights to generate an updated value of the read voltage for retrieving information from the memory device.